The present invention relates to novel unsaturated diols, a process for preparing same and a process for converting these diols to squalane.
It is well known that a diacetylene diol is prepared by subjecting an alkynol to the oxidative coupling reaction in an oxygen atmosphere in the presence of a copper-pyridine complex as a catalyst to dimerize the alkynol (J. Chem. Soc., 1974, pages 1579-1583).
The present inventors have previously described a process for synthesizing squalane which comprises subjecting an alkynol represented by the following general formula [II]: ##EQU1## wherein A and D are as defined above in the general formula [I], to an oxidative coupling reaction in an oxygen atmosphere in the presence of a known coupling catalyst, namely a copper-pyridine complex compound, to form a diacetylene dialcohol repesented by the following general formula: ##EQU2## wherein A and D are as defined above in the general formula [I], and subjecting the diacetylene dialcohol to hydrogenolysis or a combination of hydrogenation, dehydration and hydrogenation (British Patent Applications Nos. 11465/74 and 14126/74; United States patent application Ser. Nos. 448,700 and 454,694.
However, it has been found that desirable repeated use of the copper-pyridine complex compound as a catalyst is very difficult as a consequence of the problems encountered in separating and recovering the catalyst from the reaction system and because the activity of the catalyst is lowered. Further, reaction of a triple bond-containing compound such as an alkynol in a reaction system including a heavy metal compound such as copper-pyridine and oxygen always involves a danger of sympathetic detonation.